/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: wwy
 * Date: 2024-11-27
 * Time: 17:14
 */
public class MyLinkedList implements IList {
    static class ListNode {
        public int val;
        ListNode prev;
        ListNode next;

        public ListNode(int val) {
            this.val = val;
        }
    }

    public ListNode head;
    public ListNode last;

    @Override
    public void addFirst(int data) {
        ListNode node = new ListNode(data);
        if (head == null) {
            head = last = node;
            return;
        }
        node.next = head;
        head.prev = node;
        head = node;
    }

    @Override
    public void addLast(int data) {
        ListNode node = new ListNode(data);
        if (head == null) {
            head = last = node;
            return;
        }
        last.next = node;
        node.prev = last;
        last = node;
    }

    private ListNode findIndex(int index) {
        ListNode cur = head;
        while (index != 0) {
            cur = cur.next;
            index--;
        }
        return cur;
    }

    @Override
    public void addIndex(int index, int data) {
        int len = size();
        if (index < 0 || index > len) {
            return;
        }
        if (index == 0) {
            addFirst(data);
            return;
        }
        if (index == len) {
            addLast(data);
            return;
        }
        ListNode cur = findIndex(index);
        ListNode node = new ListNode(data);
        node.next = cur;
        node.prev = cur.prev;
        cur.prev.next = node;
        cur.prev = node;
    }

    @Override
    public boolean contains(int key) {
        ListNode cur = head;
        while (cur != null) {
            if (cur.val == key) {
                return true;
            }
            cur = cur.next;
        }
        return false;
    }

    @Override
    public void remove(int key) {
        if (head.next == null) {
            if (head.val == key) {
                head = last = null;
            }
            return;
        }
        ListNode cur = head;
        while (cur != null) {
            if (cur.val == key) {
                if (cur == head) {
                    head = head.next;
                    head.prev = null;
                } else if (cur == last) {
                    cur.prev.next = null;
                    last = last.prev;
                } else {
                    cur.prev.next = cur.next;
                    cur.next.prev = cur.prev;
                }
                return;
            }
            cur = cur.next;
        }
    }

    @Override
    public void removeAllKey(int key) {
//快慢指针
        if (head.next == null) {
            if (head.val == key) {
                head = last = null;
            }
            return;
        }
        ListNode cur = head;
        while (cur != null) {
            if (cur.val == key) {
                if (cur == head) {
                    head = head.next;
                    head.prev = null;
                } else if (cur == last) {
                    cur.prev.next = null;
                    last = last.prev;
                } else {
                    cur.prev.next = cur.next;
                    cur.next.prev = cur.prev;
                }
            }
            cur = cur.next;
        }
    }


    @Override
    public int size() {
        int count = 0;
        ListNode cur = head;
        while (cur != null) {
            cur = cur.next;
            count++;
        }
        return count;
    }

    @Override
    public void clear() {
        ListNode cur=head;
        while(cur!=null){
            ListNode curN=cur;
            cur.next=null;
            cur.prev=null;
            cur=curN;
        }
        last=null;
        head=null;
    }

    @Override
    public void display() {
        ListNode cur = head;
        while (cur != null) {
            System.out.print(cur.val + " ");
            cur = cur.next;
        }
        System.out.println();
    }
}
